Table of Content

10 January 2017, Volume 28 Issue 01

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Selection Function Based on Singleimpact Breakage Mass Model of Particle Beds in Ball Mills

MAO Yalang, SUN Yi, JI Shiming, SHAN Jihong, JIN Xiaohang

2017, 28(01):  2-6. 

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In order to establish the particle comminution process model and improve the grinding efficiencies in ball mills, the studies of the selection function were carried out based on the singleimpact breakage mass model. According to the nipped configurations and the falling ball impact tests, the particlebed breakage was divided into the incomplete breakage in low impact energy and the complete breakage in high impact energy. The energy of mass specific fracture energy and the effects of fine particles on nipped breakage mass were analyzed. The models of the singleimpact breakage mass under two broken states were built respectively. The selection function, which included the breakage influence factors such as media diameter, particle size and particle shape of ball mill, was set up based on the impact energy spectrum and the singleimpact breakage mass model.

Reliability Assessment Based on Competition Failure Considering Multidegradation and Catastrophic Failure

LIU Xiaojuan, WANG Huawei, XU Xuan

2017, 28(01):  7-12. 

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A reliability assessment method of the competing failure during multidegradation failure and the catastrophic failure was proposed. Covariance was used to analyze the dependence and the degree of correlation during multivariate degradation information, reliability assessment model of multidegradation mode was developed. In addition, multivariate normal distribution was used to establish the model. The conditional probability of catastrophic failure under the degradation data was developed to analyze the effects of degradation failure on catastrophic. Reliability assessment model of competition failure was developed through the joint probability distribution function of multidegradation mode and catastrophic failure. Finally, an example of the failure data of aero engine verified the effectiveness of proposed method.

Numerical Simulation and Experiments of Abrasive Flow Polishing for Nozzle Microholes

LIU Weina, CAI Zhijie, LI Yunfeng, REN Chengzu

2017, 28(01):  13-19,26. 

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Abrasive flow polishing of nozzle microholes was studied herein, and the processes were simulated by using the Mixtures turbulence model of kε solid1iquid twophase to study the flow field distribution. Through the orthogonal experiment, the effects of polishing pressures, concentration, grain sizes and processing times on the surface roughness were researched systematically. Results show that this mode of unidirectional cycle processing is applicable to improve microhole structure. The surface roughness of the flow channel has a negative correlation with each machining parameters, and is greatly affected by the polishing pressures and abrasive concentration. The optimum combination of parameters was obtained, and under this condition the surface roughness values of nozzle microholes drop to 0.20μm from 1.16μm.

Robust Optimization Design of the Mars Airbag Lander

QING Qixiang, QING Xiang, XIAO Jiuru, LIAO Huidong

2017, 28(01):  20-26. 

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Mars airbag lander was a complex structure with many critical parameters, extreme environment conditions, many uncertain factors and high reliability requirements. Computational efficiency of simulation was always a bottleneck problem in the processes of optimization design for the Mars airbag landers. Based on parallel and distributed computing technologies of super computing platforms and the multiobjective robust optimization method, a robust optimization design for the complex airbag system was carried out. The results show that the applications of supercomputer platform may greatly improve the robust optimization's computational efficiency in the optimization design, and the reliability of the Mars airbag lander will be highly improved.

Nonlinear Dynamics Modeling and Simulation of Shearer Cutting Unit Transmission System

MAO Jun, ZHANG Yu, ZHANG Kun, CHEN Hongyue, XU Jianbo

2017, 28(01):  27-34. 

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According to the phenomenon that gear transmission system of shearer cutting unit produced vibrations and noise in operation, a nonlinear dynamics model for gear transmission system of shearer cutting unit was established with the consideration of mesh stiffness, mesh damping, and comprehensive errors. Differential equations were solved by employing variable step size RungeKutta integration method. The influences of mesh stiffnesses，damping ratios and excitation frequencies on gear transmission system were studied through analyzing phase plane and Poincare section. The results show that in a certain range，displacement response of sun gear changes from single periodic motion to multiperiodic motion and then into chaotic motion with the decreasing of damping ratio. Displacement response of sun gear also gradually changes from periodic motion to chaotic motion with the increasing of mesh stiffness. Displacement response of sun gear changes from periodic response to chaotic response and then into quasiperiod response with the increasing of the excitation frequencies.

Study on Contour Shaping in Wire Microgrinding

LI Qiao, ZHU Yuanxiang, ZHOU Liwu, ZHOU Bing

2017, 28(01):  35-40. 

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In order to realize the micromachining on local area of wires, a new grinding method was proposed. Through the force condition analysis of the deflected wires, the jacking force formula was deduced. The pressure distribution in contact area and cutting depth distribution of the grains were modeled respectively. Based on the relationship between the grinding positions and the jacking forces, a deflection adjusting method was proposed to realize the grinding processes of step wires and taper wires. In a selfassembled grinding platform, machine visual was taken as measurement method, fixedposition grinding and sweeping grinding experiments were conducted. The results of fixedposition grinding show that the wire profile in grinding area is parabolic after grinding. Shape evolution of wires suggests that the pressure distribution on contact area is parabolic initially and tends to be uniformed as the grinding goes on. The wire deflection has a critical impact on the material removal rate and the shape of the parabola. The results of the sweeping grinding show that step and taper wires may be obtained with different deflection adjusting parameters.

Predicting Method for Fatigue Life with Stress Gradient

SHEN Jiebin, TANG Donglin

2017, 28(01):  40-44. 

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Aiming at the problems that existed in the predicting the fatigue life processes by the critical distance method and the stress field intensity method, taking advantages of the two methods, an equivalent stress approach was proposed, where the effective stress average in spherical regions near the notch was taken as fatigue behavior control parameters. According to a set of fatigue tests, the relationship between the equivalent stress and spherical radius was studied, results show the relationship is well represented in the form of linear and exponential functions, by defining the stress gradient and relative stress gradient, a fatigue life prediction model was constructed considering the stress gradient. Determination of parameters in the model was studied,The spherical radius with the same equivalent stress of the smooth specimen and the notched specimen was taken as the damage region size under action of fatigue limit in the same load condition.  The spherical radius was obtained without test, so this method had a strong practicality. Validation of the fatigue test results indicates that the model prediction results are within 2 fold of the dispersion bands, show that the model has good prediction accuracy; the model may also predict the fatigue damage location.

Fault Separation and Recognition of Rolling Bearings Based on Source Number Estimation and FDBD

ZHANG Jianyu, MENG Hao, XU Yonggang

2017, 28(01):  45-51. 

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According to the problems that the vibration features of bearing faults were hard to separate and recognize in strong vibration source inhibition, a diagnosis method was established based on source number estimation and FDBD algorithm. Wavelet packet decomposition was used to divide the signals into multiple sub band signals, and SVD was selected to estimate the signal source numbers in underdetermined conditions. The multiple dimension signals were constructed based on the source number estimation. The FDBD algorithm, which included STFT, fastICA in complex domain, relevance ranking and inverse STFT, was finally applied on fault feature separation and extraction. The effectiveness of the method was validated in fault feature separation and weak feature recognition  by the simulation signals and experimental data of rolling bearing faults.

Fault Diagnosis Method of Gearbox Bearings Based on Generalized S-transform

CHEN Huanguo, YI Yongyu, CHEN Wenhua, CHEN Pei, SHEN Jianyang

2017, 28(01):  51-56. 

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The signals of gear box bearing faults usually were nonstationary and nonlinear. It might be more difficult to identify and extract in the strong background signals and noises. Based on the unique features and the timefrequency concentration of the generalized S-transform, a rolling bearing fault diagnosis method was proposed based on generalized S-transform. Window function in the generalized S-transform was discussed, and the influences of different parameters in adjusting the width of window function were analyzed, and the different energy distributions of bearing faults were discussed in timefrequency spectrum by generalized S-transform. Finally, the proposed method was validated by simulation analyses and the experiments of rolling bearings. The results show that the proposed method may accurately reveal the rolling bearing fault features frequency, and provides an effective method for gear box bearing fault diagnosis.



Optimization and Simulation on Smart Temperature Controller Based on PFuzzy and I Control Algorithm

WANG Shuxin, ZHANG Hui, CHEN Guoping, WANG Hongtao, LIU Run

2017, 28(01):  57-61,81. 

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House temperature system was of large time delay and large time constant，which were hard to be controlled by traditional control methods. A PFuzzy and I controller applied in smart temperature controller for carbon fiber electric floor heating system was proposed herein.The operation principles of the PFuzzy and I controller was elaborated. The control algorithm mixed fuzzy with PID was designed in detail. MATLAB simulation results show, PFuzzy and I controller has shorter adjustment time, lower overshoot, higher static and dynamic performance, as well as better robustness than switch, PID and Fuzzy controller.

Friction Compensation of Proportional Multiway Valve Based on Modified Viscous Friction LuGre Model

CHEN Dongning, LIU Yidan, YAO Chengyu, JIANG Donglin, WANG Kexun,

2017, 28(01):  62-68. 

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To decrease the influences of friction on the proportional multiway valves, the methods of friction characteristic analysis, parameter identification and friction compensation of proportional multiway valves were proposed based on modified viscous friction LuGre model. The friction data were indirectly obtained through the experimental tests. The static and dynamic parameters of modified viscous friction LuGre model were identified by data fitting. The friction state observer of modified viscous friction LuGre model was designed by use of the identified parameters, and the output of state observer was fed back to the input port of control model to reduce the adverse effect of friction on the proportional multiway valve performances. Simulation results show that the location tracking accuracy of proportional multiway valves may be improved by using the friction compensation with identification parameter method based on modified viscous friction LuGre model.

Improvement of SSI Algorithm Based on Extraction of Modal Parameters

LI Yugang, YE Qingwei, ZHOU Yu, FANG Ning

2017, 28(01):  69-74. 

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SSI algorithm played an important role in the large structure vibration detection and damage identification. Sparse optimization solution was introduced to replace the least square method that was used to get sparser state matrix. Kmeans algorithm was introduced to elect real modal parameters from many modal parameters so as to eliminate the false modals effectively. The experimental results show that optimization solution of SSI algorithm may accurately extract modal parameters. The work herein has reference values in engineering applications.

Autofrettage Analysis of Thick-walled Cylinder Based on Triple-shear Unified Strength Criterion

CAO Xueye, ZHAO Junhai, ZHANG Changguang

2017, 28(01):  75-81. 

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In order to analyze autofrettage theory of thick-walled cylinders, a bilinear hardening model was established and the analytical solutions of loading stresses, residual stresses and working stresses were derived based on the triple-shear unified strength criterion, which taken the strain hardening, Bauschinger effect, strength difference(SD) effect and the effect of intermediate principal stress into consideration. The optimal autofrettage pressure of thick-walled cylinder was deduced, the influences of ratio among tension stress and compression stress, strength criterion parameters were investigated respectively. In addition, the stress distributions of thick-walled cylinders between autofrettage and non-autofrettage, the bilinear hardening model and elastic-perfectly plastic model were compared. The results show that the optimum autofrettage pressure will increase with the increase of radius ratio and strength criterion parameter；the maximum equivalent working stress will decrease with the increase of radius ratio and strength criterion parameters, but increases with the increase of ratio between tension stress and compression stress; the maximum equivalent stresses in the elastic plastic junctions and the stresses of thick-walled cylinder along the wall thickness are well- distributed; compared with the elastic-perfectly plastic model，the radius of elastic plastic junction and residual stress of bilinear hardening model are lower, meanwhile with the increase of autofrettage pressure, the difference becomes more and more obvious; the curve of equivalent stress along with radius ratio may provide reference for choosing the optimal wall thickness; autofrettage technique may improve the working stress distribution and ultimate bearing capacity of thick-walled cylinders.

Fabrication and Properties of Superhydrophobic Surface on Aluminum Alloys Substrates by Brush Plating and Laser Processing Technology

LI Jing, ZHAO Yanhui, YU Huadong, DU Feng, WAN Yanling

2017, 28(01):  82-87,92. 

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A superhydrophobic surface on aluminum alloys substrates was fabricated by brush plating and laser processing technology. The special microstructure surface was clearly uniformly covered by many convex hull and grooves arrangement. It is found that the sample surface has low adhesion performance without any chemical modified. The water contact angle of the fabricated surface is up to 156° and sliding angle is about 4.8°. In addition, the superhydrophobic surface has anisotropy (the direction of vertical groove and parallel groove) in sliding. The studies of the stability properties of superhydrophobic surface under different temperature environments show that, the contact angle of the superhydrophobic surface may also reaches 138° under the low temperature conditions. It has shown excellent antiicing performance. The corrosion inhibition property of superhydrophobic coating in 3.5% NaCl solution is examined by Tafel curve measurement, and results show that, the special surface structure of aluminum alloy corrosion resistant value improves 3 orders of magnitude.

Study on Posture Solution Method of Automatic Assembly of Cabins

JIN Herong, LIU Da, YU Bin, FAN Xiubin

2017, 28(01):  88-92. 

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The accurate posture of spacecraft cabins in the assembly spaces should be determined in the spacecraft assembly production. Taking cylinder class spacecraft cabin structure as an example, a vector posture solving method was proposed to realize the accurate solution of cabin's postures. By laying reasonable feature points on the cylindrical surfaces of cabins, the position vector of origin of bodyfixed coordinate system of cabins in the assembly space was solved using the damped least square method. The rotation matrix of bodyfixed coordinate system of cabins was solved combined with the space cylindrical surface equations, and then the six pose parameters of cabin were obtained. The numerical simulation was conducted on the cabin using the proposed method and the simulation results show its validity and accuracy.

Analysis for Load Distribution of Tandem Cold Rolling Based on Constrained Multiobjective Evolutionary Algorithm

SUN Hao, XIAO Hong, HU Qingjun

2017, 28(01):  93-100. 

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The load distribution of tandem cold rolling might be abstracted as a constrained multiobjective optimization problem. To solve this problem, an evolution algorithm was proposed based on environmental Pareto dominated selection strategy. The algorithm which accelerated the convergence speed by excellent infeasible solutions gave a more objective evaluation of the different solutions. Taking the power margin, minimum total rolling energy consumption, minimum slip factor and the best rolling force at last rack as optimizing criterion, the quantitative relationship among four objective functions was obtained by the constrained multiobjective evolutionary algorithm, which made decisionmaker grasp the rules of rolling intuitively without proficient in complex rolling theory knowledge. And the necessity of the multiobjective strategy in the load distribution of tandem cold rolling was illustrated.

Simulation and Experiments of Binding Strength of Different Binding Interfaces on ZChSnSb11-6/20 Steel Composites

WANG Yao, XIANG Dan, MENG Wenjun,

2017, 28(01):  101-106,112. 

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The theoretical calculation models of different binding interfaces(under different processing conditions for production) on working binding strength were established based on the composite of steel body and Babbitt layer. The simulations of stress fields for different binding interfaces were carried out by COMSOL Multiphysics software based on small units as buildable models. The interfacial stress distribution of different processing conditions for production was obtained. Simulation results reveals the relative errors of three kind of binding interfaces between theoretical formula and simulation were within the range of 15%. ZChSnSb11-6/20 steel composites with different binding interfaces and different roughnesses were prepared by arc spraying technology. And the permissible binding strengths of different binding interfaces were obtained. Experimental results reveal the binding strength increases with contact area of binding interface increased for the same roughness. The binding strength of arc-binding interface(type B) binding interface was closer to that of segment of spherical interface(type C) and the difference is within 2 MPa. However, the binding strength is the minimum for smooth interface(type A) binding interface. And the difference is about 60% compared with type B or type C binding interface. Then the constructed model was evaluated by comparative analysis and the table for model evaluation was obtained.

Incar AAP Test Bench Based on RTWT

LIN Qingfeng, ZHAO Yunhui, LI Shengbo

2017, 28(01):  107-112. 

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To develop an AAP test bench using RTWT, the following three steps were adapted.  First, the mechanisms and transmission parameters of the AAP mechanical device were designed. Second, the hardware and programs of the electronic control system were developed using rapid control prototype (RCP) technology based on MATLAB/RTWT. Finally, the force feedback and stiffness feedback functions of the AAP were verified by experiments. The results show that the AAP test bench has good reliability and validity.

Optimization of APU Startstop Control for Diverse Mileage Ranges

LIN Xinyou, ZHANG Shaobo, FENG Qigao

2017, 28(01):  107-112. 

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For a rangeextended electric vehicle, a multi point energy management strategy was developed to meet different demands of power and energy. Then an optimization model of APU was formulated to achieve the target of minimum fuel consumption. In the constraints of performance index of rangeextended electric vehicle and battery cycle life, optimization of control parameters of APU startstop was performed by the SIMULINK model with diverse mileage ranges under different driving cycles to realize APU startstop control for adaptive range. Compared with before optimization，the results show that fuel consumption is reduced by 15.87%/2.09%，42.24%/14.54% respectively corresponding to NEDC100/200,CUDC100/200. Based on energy consumption comparisons before and after optimization，the fuel economy may be obtained through reducing APU operation time under the condition of single loads and transferring operation time from peak loads to medium loads and low loads under the condition of multiple loads.